8.11Java入门--->第十七节

1、集合(容器的一种)

List特有方法

//将集合抓换成数组
//        Object[] oarr = c1.toArray();

//判断集合中是否包含指定元素(equals)
        boolean b = c1.contains("nnn");

//将元素转换成集合
//        Collection c3 = Arrays.asList(1,2,3,4,5,6);

//普通方法
add();
remove();
//替换特定下标内容
set(0,123);

2、链表

addFirst
addLast

import java.util.ArrayList;
import java.util.Scanner;

public class Test005 {
    private static int testId=0;
    private static ArrayList<Count> arrayList=new ArrayList<Count>();
    private static String name;
    private static String num;
    private static String password;
    private static boolean l2;
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        while(true){
            ssout();
            System.out.println("请输入序号");
            int i=scanner.nextInt();
            if (i==0){
                System.out.println("您选择的是开户");
                account();
                continue;
            }
            if (i==1){
                System.out.println("您选择的是查询");
                select();
                continue;
            }
            if (i==2){
                System.out.println("您选择的是存款");
                add();
                continue;
            }
            if (i==3){
                System.out.println("取款");
                sub();
                continue;
            }
            if (i==4){
                System.out.println("退出");
                return;
            }
            if (i!=1&&i!=2&&i!=3&&i!=4){
                System.out.println("输入错误重新输入");
                continue;
            }
        }
    }

    public static void ssout(){
        System.out.println("************提示***********");
        System.out.println("输入0：开户");
        System.out.println("输入1：查询");
        System.out.println("输入2：存款");
        System.out.println("输入3：取款");
        System.out.println("输入4：退出");
        System.out.println("**************************");
    }
    public static void account(){
        Count count=new Count();
        Scanner scanner=new Scanner(System.in);
        System.out.println("请输入您的姓名：");
        name=scanner.next();
        count.name=name;
        System.out.println("请输入您的身份证号：");
        num=scanner.next();
        int i=num.length();
        if (i!=18){
            System.out.println("身份证号输入错误，返回上一级");
            return;
        }
        count.id=num;
        System.out.println("请输入您的密码：（密码为6为纯数字）");
        password=scanner.next();
        String s=password+"";
        int test=s.length();
        if (test!=6){
            System.out.println("密码输入错误，返回上一级");
            return;
        }
        count.password=password;
        arrayList.add(count);
        System.out.println("开户成功");
    }
    public static void select(){
        Scanner scanner=new Scanner(System.in);
        System.out.println("请输入您的身份证，系统将对您的身份践行验证：");
        boolean l1=true;
        boolean lTest=false;

        while(l1) {
            String testNum = scanner.next();
            for (int i = 0; i < arrayList.size() ; i++) {
                if (arrayList.get(i).id.equals(testNum)) {
                    testId = i;
                    lTest = true;
                }
            }
            if (lTest) {
                for (int j = 0; j <= 3; j++) {
                    if(j==3){
                        System.out.println("输入错误过多，退出程序");
                        l2=false;
                        return;
                    }
                    System.out.println("输入密码，共有三次机会，第"+(j+1)+"次");
                    String testName=scanner.next();
                    String s=password+"";
                    if(arrayList.get(testId).password.equals(testName)){
                        System.out.println(arrayList.get(testId).name+"您好");
                        System.out.println("您的余额是"+arrayList.get(testId).sum);
                        System.out.println("您的身份证是"+arrayList.get(testId).id);
                        return;
                    }else {
                        System.out.println("输入错误");
                        continue;
                    }
                }
            } else {
                System.out.println("error输入错误，重新输入");
                continue;
            }
        }
    }
    public static void add(){
        Scanner scanner=new Scanner(System.in);
        l2=true;
        select();
        if (l2==false) return;
        System.out.println("****************");
        System.out.println("输入存款金额");
        int i=scanner.nextInt();
        if (i<0){
            System.out.println("无效，自动退出");
            return;
        }else {
            arrayList.get(testId).sum+=i;
            System.out.println("余额："+arrayList.get(testId).sum);
        }
    }
    public static void sub(){
        Scanner scanner=new Scanner(System.in);
        l2=true;
        select();
        if (l2==false) return;
        System.out.println("****************");
        System.out.println("输入取款金额");
        int i=scanner.nextInt();
        int s= arrayList.get(testId).sum;
        if (i<0||i>s){
            System.out.println("无效，自动退出");
            return;
        }else {
            arrayList.get(testId).sum-=i;
            System.out.println("钱你是拿不到的，但是余额会扣");
            System.out.println("余额："+arrayList.get(testId).sum);
        }
    }

 

package com.xian.dao;

public class Count {
    String id;
    String name;
    String password;
    int sum=100;

    public Count() {
    }

    public Count(String id, String name, String password) {
        this.id = id;
        this.name = name;
        this.password = password;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "Count{" +
                "id='" + id + '\'' +
                ", name='" + name + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

新建类三件套，空构造，有参构造，get and set,toString,不管用的上用不上，写上再说